In related-art technology, a polarizer plate protective film is bonded to each side of a polarizer in order to improve the durability of the polarizer. The polarizer plate protective film is required to exhibit high tenacity and high surface hardness. In general, a polymer exhibiting high surface hardness has a high flexural modulus, but is fragile. Therefore, when using a polymer exhibiting high surface hardness as the material for the polarizer plate protective film, cracks tend to occur when forming the polarizer plate. On the other hand, when using a polymer exhibiting high tenacity as the material for the polarizer plate protective film, the resulting polarizer plate protective film exhibits insufficient surface hardness. Therefore, a known polarizer plate protective film is generally produced by using a polymer with a low modulus of elasticity as a base film and forming a hard coating layer on the surface of the film in order to improve surface hardness.
In this method, after forming the base film, a hard coating layer forming solution is applied and dried (and cured in some cases) to form the hard coating layer. However, since it is necessary to form a hard coating layer to a large thickness in order to provide the hard coating layer with sufficient hardness, production becomes complicated, whereby the yield decreases.
In order to solve this problem, a multilayer polarizer plate protective film has been proposed which is produced by stacking resins to make the most of the properties of each resin (e.g. JP-A-2000-206303 and JP-A-2002-249600). However, the polarizer plate protective film disclosed in these documents also has a problem in terms of the balance between surface hardness and tenacity, whereby cracks may occur when forming the polarizer plate.
The present invention has been achieved in view of the above-described situation of the related art. An object of the present invention is to provide a polarizer plate exhibiting high tenacity and high surface hardness, and a liquid crystal display device including the polarizer plate and a liquid crystal cell.